Storage system



STORAGE SYSTEM 3 Sheets-Sheet l Filed Aug. 8, 1963 sept 22, 1964 H. w. MGCALL ETAL 3,149,472

STORAGE SYSTEM 3 Sheets-Sheet 2 Filed Aug. 8, 1963 Wwf@- wd Sept' 22, 1954 H. w. MCCALL ETAL l 3,149,472

sToRAGE SYSTEM Filed Aug. 8, 1963 3 Sheets-Sheet 5 Ava .3i i 29 2 i wv M i /7/0 www 24'/ M@ 527// (War/@J Af. aJ/ey Rabe/ l/V. Za/f/n/a/f 4 A?, 25 INVENTJ /f 24 BY fr United States Patent O 3,149,472 STORAGE SYSTEM Howard W. McCall, New York, NX., and Charles H.

Lashley and Robert W. Zumwalt, Shreveport, La., assignors to Texas Eastern Transmission Corporation,

Shreveport, La., a corporation of Delaware Filed Aug. S, 1963, Ser. No. 369,810

3 Claims. (Cl. 62-55) This invention relates to low temperature storage systems, and more particularly to a storage system with a novel pump assembly for lifting liquid within the system.

Low temperature storage systems are used for many liquids, such as liquefied natural gas, and this invention will be explained in conjunction with its use in an underground liquefied natural gas storage system, but it will be understood that it can be utilized in other systems where similar problems are present.

For various and sundry reasons, liquefied natural gas is preferably stored underground. This type of storage minimizes lire hazards, etc., as more specifically pointed out in copending application Serial No. 256,491, filed Feb. 4, 1963, which application is referred to for a more detailed discussion of the problems and construction of underground storage facilities.

The low temperature liquid stored in these facilities will boil off when the temperature is permitted to rise. ln point of fact, there is a constant slight boiloE which is normally taken to the refrigeration equipment and reliqueied. Thus, at any time that the tank is open, there is a tendency for the stored liquid to boil off at the opening. This boiloff gas is, of course, highly inflammable.

As the lifting pumps for lifting liquid from the tank require maintenance from time to time, some means should be provided for permitting maintenance work to be carried out on these pumps without the presence of dangerous gas during removal of the pump if it is completely removed, or during work on the pump if it is necessary to only partly remove it.

It is an object of this invention to provide a storage tank with a pump which can be partially or completely removed without danger from boilotf gases.

It is another object to provide a storage tank with a pump well in which a pump is positioned for lifting fluid and in which this pump is automatically in communication with the tank when in position, and in which the well is automatically closed when the pump is removed.

Another object is to provide a storage system as in the preceding object in which provision is made for removing boiloff gas from the pump well before the pump is completely removed.

Another object is to provide a storage system as in the preceding object in which provision is made for passing purge gas into' the pump well before the pump is removed to insure that all inflammable gases have been removed.

Another object is to provide a storage tank with a pump in a pump well in which the amount of liquid which can accumulate in the pump Well is limited to minimize the boilo of gas after the pump well is closed preparatory to removing the pump.

Other objects, advantages and features of this invention will be apparent from the drawings, the specification and the claims.

In the drawings, wherein an illustrative embodiment of 3,149,472 Patented Sept. 22, 1964 ice this invention is shown, and wherein like reference numerals indicate like parts:

FIGURE 1 is a miniature elevational view of a tank and pump incorporating this invention, with a portion of the overhead dirt cover removed;

FIGURES 2A and 2B are continuation views, partially in elevation and partially in vertical cross-section, through a fragment of the tank and pump illustrated in FIGURE 1, and showing the pump in operating position;

FIGURE 3 is `an enlarged fragment-ary View partially in elevation and partially in vertical cross-section, illustrating details of the apparatus shown in FIGURES 2A and 2B; and,

FIGURE 4 is a fragmentary sectional view illustrating a preferred form of seal for the valve member at the bottom of the pump well.

FIGURE 1 illustrates at 10 an underground storage tank which may be constructed of concrete, or the like, and suitably insulated to store liquids such as liquefied natural gas. The pump, indicated generally at 11, is provided for lifting liquid from the tank. It will be understood that the tank and pump will normally form a part of a low temperature storage system which will include refrigeration and other ancillary equipment, as will be understood by those skilled in the art.

Referring to FIGURES 2A and 2B, the tank 10 includes the side annular wall 12 supported upon a bottom 13. The tank is completed by a top 14. The tank may be of any desired construction, but is preferably constructed of concrete.

Suitable insulation is provided for insulating the tank to minimize heat transfer. This insulation includes the lower insulation material 9 over the bottom of the tank, the side wall insulation 15 and the top insulation 16. To protect the bottom insulation while working in the tank, it is preferably covered with a layer of plywood 17 and a slab of concrete 18 is poured over the plywood, and the concrete slab has suiicient weight to overcome the natural buoyancy of the wood and insulation material.

The top 14 is provided with an opening 19 in which a pump well 21 is secured by the bolt and nut assembly indicated generally at 22. The pump 11 is mounted in pump well 21,

A check valve is provided at the bottom of the pump well 21. This valve is open when the pump is in position as indicated in FIGURE 2B, and is closed when the pump is raised as indicated in FIGURE 3. When the cheek valve is open, the tail pipe 23 of the pump is in fluid communication with the interior of the tank. When the pump 11 and tail pipe 23 are raised, the check valve closes to exclude liquid from the tank from the pump well.

Preferably, the check valve is provided by a check valve member 24 which is essentially a fiat plate cooperating with the lower end 25 of the pump well which provides a valve seat.

As best shown in FIGURE 4, a suitable seal member 26 is preferably locked in the valve member 24 by a dovetail construction and seats in a groove 27 in the bottom 25 of the pump well 21. This seal member may be constructed of any material which will withstand the low temperature conditions in the tank. Normally it will be found that one of the plastics, such as Teon, will be satisfactory.

Means are provided for closing the check valve 24 upon raising of the tail pipe 23. This means may be associated with suitable guides guiding the check valve in its vertical movement. Preferably, this assembly includes a plurality of spaced lugs 28 and 29 carried on the pump well 21 cooperating with upstanding guide rods 31 carried by the valve member 24 and slidable within the lugs 28 and 29. A plurality of springs 32 are compressed between lugs 29 and stop washers 33 on the upper ends of the guide rods 31.

Normally, the pump well will have a substantial vertical dimension, and it ispreferred to stabilize the lower end of the pump well in the bottom of the tank. For this purpose, suitable stabilizing means is provided between the bottom of the tank and the pump Well 21 or the valve member 24. As illustrated in the drawings, a simple form of stabilizing may be provided by a plurality of upstanding guide rods 34 secured in slab 13 which slidably engage the valve member 24 and through the valve member and its cooperating guide rod and lug structure stabilize the lower end of the pump well 21. Preferably, the guide rods 34 slide within suitable holes 35 in the valve member 24.

In order to prevent, insofar as possible, flow of liquid into the annulus between the tail pipe 23 and the pump well 21, a seal is preferably provided between the lower end of the tail pipe and the pump well. In the illustrated embodiment a Teflon seal 36 is provided in the lower end of the well and has a sliding seal engagement with the lower end of the tail pipe provided by the enlarged section 37. The tail pipe also has a shoulder 38 which extends radially outwardly beyond the surface 37 and engages the top of the seal 36 to seal therebetween.

It will be appreciated that when the tail pipe is in its lower position, a seal will be provided both by the shoulder 38 and the sliding surface 37 with the seal member 36 to prevent flow of liquid up into the annulus between the tail pipe and well. As the tail pipe is raised, the sliding seal will limit flow of uid into the annulus between the tail pipe and well until the check valve member 24 is seated, and preferably for this purpose the seal 36 Vhas a Vertical dimension greater than the normal travel of the check Valve member, as shown in FIGURE 3.

Referring now to the top of the pump assembly as ,shown in FIGURE 2A and FIGURE 3, it will be noted that provision is made for limited vertical movement of the pump in an amount which will permit the check valve 24 to close. This vertical movement may be provided by suitable jacks, not shown, cooperable with jack lugs such as shown at 20, or any other desired means. The upper end 21a of the pump well has secured thereto a ring 39. This ring has an inwardly directed ange 41. By comparing FIGS. 2A and 3, it will be apparent that the channel 42, which has its lower flange 42a outturned into the ring 41, is vertically reciprocal between a position in which the pump and tail pipe are in a selected lower position to open the check valve 24, and a selected upper position in which the check valve 24 is closed. A suitable seal 43 is provided for sealing between the channel 42 and the ring 41 when the channel is in the upper position. In like manner, a suitable seal 44 is provided for sealing between the upper end 21a of the well and channel when the channel is in its lower position. If desired, sliding seals could be provided for sealing between the ring and the channel during the jacking action. These are not shown, as the chances of gas escaping during this time are extremely limited.

To minimize heat loss through the pump well, it is preferred that the annulus between the pump well 21 and the tail pipe 23 be insulated. For this purpose, a suitable block of insulation 45 is carried by channel 42. Preferably, the block of insulation is carried in a supporting annular channel 46 which is welded to the channel 42. By a comparison of FIGURES 2A and 3, it will be noted that when the pump is in its lower operating po'- sition, the insulation material is positioned opposite the i upper portion of the concrete Well 19, to thus minimize heat loss at this point in the tank. When the pump is raised, the insulation block 4S moves up to a position opposite the ring 39.

Suitable means are provided for purging the annulus between the tail pipe 23 and the Well 21 by one or more conduits 47 and 48. These conduits provide entry into the distribution chamber 49 provided by the interior of the ring 39. A suitable plurality of passageways 51 extend from the bottom of the block of insulation material 45 to the side wall of the insulation block at a point where they are in communication with the chamber 49, and thus the conduits 47 and 48.

The operation of removing the pump will be explained, and it will be understood that the reverse operation is carried out for installing the pump.

Suitable jacks lift the pump and tail pipe from the position of FIGURES 2A and 2B to the position of FIG- URE 3. During this time the sliding seal between the seal 36 and the surface 37 on the tail pipe limit entry of fluid into the tail pipe. As the pump moves up, the valve 24 is urged upwardly by springs 32 and closes the lower end o-f the pump well. When the pump reaches the upper jack position, the surface 37 will move out of sliding engagement with the seal member to thus establish communication between the area immediately above the check Valve 24 and the remainder of the pump well. At this time, the seal 43 will seal between the channel 42 and ring 39, and the pump well will remain sealed. The conduits 47 and 48 are now utilized to pump purge gas into the pump well through these conduits and the several passageways 51. This purge gas may be directed through the pump to clear the pump. As the purge gas sweeps down through the tail pipe Well annulus, it will sweep out all of the gas therein, and as it moves down past the sliding Seal 36, it will insure that all of the gas in this area is swept on out through the pump. Of course, as the relatively high temperature purge gas Yreaches the check valve 24, all of the liquid within the pump will rapidly boil off and all of the liqueied natural gas will be gassied and all of the gas removed from the well. At this time the nuts 22a of the hold-down assembly 22 may be removed, and the pump and ring 39 lifted off together to pull the pump completely from the well for repair or replacement. Of course, if desired, the pump may be worked on in place with safety after the pump and well have been purged, as all of the inammable gas will have been removed. If desired, a slight amount of inert gas may continuously be passed through :the system while the pump is being worked on in place to insure that any natural gas which may possibly find its way past the check valve 24 will be diluted to a noninammable mixture and swept out of the system.

This invention also provides denite advantages in above-ground systems. It is preferred to remove liquid through the top in above-ground systems because of insulation problems. Where valved openings are provided below the liquid level in the tank they are hard to insulate, and a break in insulation requires that the tank be emptied for repairs if internal insulation is used. Where the liquid is removed from the top of the tank, these problems are overcome, and therefore apparatus in accordance with this invention will preferably be used in aboveground tanks.

The foregoing disclosure and description of the invention is illustrative and explanatory thereof, and various changes in the size, shape .and materials, as well as in the details of the illustrated construction, may be made within the scope of the appended claims without departing from the spirit of the invention.

What we claim is:

l. A'storage system comprising,

a storage tank,

a pump well depending from the top of said tank,

a check valve in the bottom of said pump well,

means urging said check valve toward closed position,

a pump mounted in the pump well and having a tail pipe extending to the bottom of the well and engaging said check valve and holding it in open position when said pump is in a first lower position,

said tail pipe when raised to a second higher position permitting said check valve .to close due to the force exerted by said urging means,

and at least one conduit connecting the interior of said pump well to the exterior of said tank for the introduction of a purge iluid into said pump well.

2. A storage system comprising,

a storage tank,

a pump well depending from the top of said tank,

a check valve in the bottom of said pump well,

means urging said check valve toward closed position,

a pump mounted in the pump well and having a tail pipe extending to the bottom of the well and engaging said check valve and holding it in open position when said pump is in a rst lower position,

said tail pipe when raised to a second higher position permitting said check valve to close due to the force exerted by said urging means,

at least one conduit connecting the interior of said pump well to the exterior of said tank for the introduction of a purge uid into said pump well,

a block of insulation material extending between the tail pipe and said pump well, i

and a passageway through said block of material in communication with said conduit when said tail pipe is in said second position and out of communication with said conduit when said pump and tail pipe are in said irst position.

3. A storage system comprising,

a storage tank,

a pump well depending from the top of said tank,

a check valve in the bottom of said pump well,

means urging said check valve toward closed position,

a pump mounted in the pump well and having a tail pipe extending to the bottom of the well and engaging said check valve and holding it in open position when said pump is in a irst lower position,

said tail pipe when raised to a second higher position permitting said check valve to close due to the force exerted by said urging means,

at least one conduit connecting the interior of said pump well to the exterior of said tank for the introduction of a purge fluid into said pump well,

and a sliding seal between the lower end of the tail pipe and pump well.

4. A storage system comprising,

a storage tank,

a pump well depending from the top of said tank,

the bottom of said well providing a check valve seat,

a check valve member cooperable with said valve seat when seated to prevent tiow of fluid into said well,

means urging said check valve toward closed position,

a pump mounted in the pump well and having a tail pipe extending to the bottom of the well and engaging said check valve member and holding it in open position when said pump is in a iirst lower position,

said tail pipe when raised to a second higher position permitting said check valve to close due to the force exerted by said urging means,

and at least one conduit connecting the interior of said pump well to the exterior of said tank for the introduction of a purge uid into said pump well,

5. A storage system comprising,

a storage tank,

a pump well depending from the top of said tank,

the bottom of said well providing a check valve seat,

a check valve member cooperable with said valve seat when seated to prevent flow of uid into said well,

means guiding the valve member vertically between open and closed position,

means on the bottom of said tank having a releasable engagement with one of said pump well and Valve member for stabilizing the bottom end of said pump well,

means urging said check valve toward closed position,

a pump mounted in the pump well and having a tail pipe extending to the bottom of the well and engaging said check valve member and holding it in open position when said pump is in a first lower position,

said tail pipe when raised to a second higher position permitting said check valve to close due to the force exerted by said urging means,

and at least one conduit connecting the interior of said pump well to the exterior of said tank for the introduction of a purge fluid into said pump well.

6. A storage system comprising,

a storage tank,

a pump well depending from the top of said tank,

the bottom of said well providing a check valve seat,

a check valve member cooperable with said valve seat when seated to prevent iiow of uid into said well,

means urging said check valve toward closed position,

a pump mounted in the pump well and having a tail pipe extending to the bottom of the well and engaging said check valve member and holding it in open position when said pump is in a first lower position,

said tail pipe when raised to a second higher position permitting said check valve to close due to the torce exerted by said urging means,

at least one conduit connecting the interior of said pump well to the exterior of said tank for the introduction of a purge fluid into said pump well,

and a sliding seal between the lower end of the tail pipeand pump well.

7. A storage system comprising,

a storage tank,

a pump well depending from the top of said tank,

the bottom of said well providing a check valve seat,

a check valve member cooperable with said valve seat when seated to prevent flow of fluid into said well,

upstanding guide rods on said valve member and guide lugs on the pump well cooperable to guide the valve member vertically between closed and open position,

upstanding guide rods on the bottom of said tank slidably engaging said valve member to stabilize the lower end of said pump well,

means urging said check valve toward closed position,

a pump mounted in the pump well and having a tail pipe extending to the bottom of the well and engaging said check valve member and holding it in open position when said pump is in a rst lower position,

said tail pipe when raised to a second higher position permitting said check valve to close due to the force exerted by said urging means,

and at least one conduit connecting the interior of said pump well to the exterior of said tank for the introduction of a purge uid into said pump well.

8. A storage system comprising,

a storage tank,

a pump well depending from the top of said tank,

the bottom of said well providing a check valve seat,

a check valve member cooperable with said valve seat when seated to prevent flow of fluid into said well,

upstanding guide rods on said valve member and guide lugs on the pump well cooperable to guide the valve member vertically between closed and open position,

upstanding guide rods on the bottom of said tank slidably engaging said valve member to stabilize the lower end of said pump well,

means urging said check valve toward closed position,

a pump mounted in the pump well and having a tail pipe extending to the bottom of the well and engaging said check valve member and holding it in open position when said pump is in a first lower position,

said tail pipe when raised to a second higher position permitting said check valve toclose due to the force exerted by said urging means, at least one conduit connecting theY interior of said pump well to the exterior of said tank for the introduction of a purge uid into said pump Well,

A a sliding seal between Vthe lower end of the tail pipe and pump well,

a block of insulation material extending between the tail pipe and said pump well,

and a passageway through said block of material communicating with said one conduit when said tail pipe Y Ais in said second position and out of communication with said conduit when said tail pipe is in said iirst position.

5 References Cited in the file of this patent UNITED STATES PATENTS 2,384,254 MeredeW Sept. 4, 1945 2,420,315 Holt May 13, 1947 2,916,889 Sattler Dec. 15, 1959 10 2,978,150 Doelcher Apr. 4, 1961 

1. A STORAGE SYSTEM COMPRISING, A STORAGE TANK, A PUMP WELL DEPENDING FROM THE TOP OF SAID TANK, A CHECK VALVE IN THE BOTTOM OF SAID PUMP WELL, MEANS URGING SAID CHECK VALVE TOWARD CLOSED POSITION, A PUMP MOUNTED IN THE PUMP WELL AND HAVING A TAIL PIPE EXTENDING TO THE BOTTOM OF THE WELL AND ENGAGING SAID CHECK VALVE AND HOLDING IT IN OPEN POSITION WHEN SAID PUMP IS IN A FIRST LOWER POSITION, SAID TAIL PIPE WHEN RAISED TO A SECOND HIGHER POSITION PERMITTING SAID CHECK VALVE TO CLOSE DUE TO THE FORCE EXERTED BY SAID URGING MEANS, AND AT LEAST ONE CONDUIT CONNECTING THE INTERIOR OF SAID PUMP WELL TO THE EXTERIOR OF SAID TANK FOR THE INTRODUCTION OF PURGE FLUID INTO PUMP WELL. 